マナマコの付着基質選択の季節性

Laboratory observations of substrate selection of Japanese sea cucumber Apostichopus japonicus in two seasons

Creators Yamana Yusuke

Creators Hamano Tatsuo

Creators Goshima Seiji

To examine the presence of any seasonal change of attachment site selection, adult Japanese sea cucumber Apostichopus japonicus were tested for their distribution patterns in two seasons, the low water temperature season (16℃) and the high (26℃). Animals were separately accommodated in circular tanks, in which substrates were prepared one half of the floor and the other half was blank. Attachment site was observed for five days at intervals of every three hours, and the number of attachment times was compared between the substrate side and the blank. A seasonal change of selection was recognized for several of the substrates. A remarkable change was observed : animals showed an aversion to sand in the high water temperature season only. We suggest that the characteristics of substrate, light condition, and coloration play an important role in the attachment site selection of A. japonicus, and the seasonal distribution pattern of wild animals is considered to follow such habitat selection.

[ISSN]0370-9361